Flavia Pennetta defeated countrywoman Roberta Vinci 7-6(4), 6-2 to win her first grand slam singles title at the U.S. Open. Moments later, Pennetta announced that she would be retiring at the conclusion of the 2015 tennis season.

Coming in...

Coming into this final, both women have battled their way past quality opponents.

For Roberta Vinci, it has been a memorable last two weeks for the Italian number three. In the first three rounds of the tournament, Vinci had to fight past Vania King in straight sets and Denisa Allertova and Mariana Duque-Marino in three sets to advance to her third fourth round appearance at Flushing Meadows. In the fourth round, the Italian was slated to play Eugenie Bouchard but Bouchard withdrew due to a concussion. Now in her third career quarterfinal at the U.S. Open, Vinci had to battle from a set down to defeat Kristina Mladenovic, to make her maiden grand slam singles semifinal. Roberta's semifinal was originally scheduled to be played on Thursday night but inclement weather pushed the match to Friday afternoon. In that semifinal, Vinci would play the overwhelming favourite in Serena Williams. The world number one was attempting to get one step closer to winning the rare Calendar Grand Slam. However, Vinci was the better player in that match, defeating Williams in undoubtedly the biggest upset of the 2015 season thus far. As a result, she would make her maiden Grand Slam singles final.

For Flavia Pennetta, it's been a very challenging path to the showpiece. Pennetta got the better of Jarmila Gajdosova, the tricky Monica Niculescu, Petra Cetkovska and Samantha Stosur - whom she has never lost to in their seven meetings. All of these tough wins in the brutal heat of New York City meant that the current Italian number two gave herself another chance to go far in the U.S. Open, her most consistent Grand Slam. In the quarterfinals, she would face Petra Kvitova. Pennetta had trouble with Kvitova's pace early on but she refused to go down without a fight, defeating her tired-looking Czech counterpart in three sets. As a result, the Italian from Brindisi booked her place in her second career U.S. Open semifinal, in singles. Pennetta would face Simona Halep for a place in the final and the world number 26 completely blew the world number two off the court, winning in straight sets to advance to her first Grand Slam singles final.

Coming into this final, both women are coming off of big wins against the two best players in women's tennis right now. Who will be able to regroup the quickest after having just over 24 hours to prepare for the biggest match of their respective careers?

Tight First Set Goes the Way of Pennetta

To begin the match, both women looked very comfortable given how big this match meant for both of them. The first four games went with the server but at two-all, Pennetta pounced and gave herself the first break points of the match in Vinci's third service game. The world number 26 needed seven chances to break, but in the end, it was a case of lucky number seven for Pennetta. Now up 3-2, Flavia continued her dominance in her own service games, holding to love to consolidate the break. Vinci, who has had her back against the wall so many times in the last two weeks, refused to give up, as she replied with a hold of her own. Pennetta, who had been so solid in her own service games today, was beginning to feel the pressure, and it showed. Vinci only needed one break point opportunity to get the break back. Now tied at four-games-all, the unseeded Italian was looking to get her nose back in front, and she did just that. Now with a spring in her step again, Vinci began to play more aggressively and held to go up 5-4. Despite this, Pennetta did not let the last couple of games affect her at all. The world number 26 began to construct points better and would go on to hold for 5-all. From there, both players were fighting hard to hold their own serve, as they were engaged in long and entertaining rallies. In the end, the first set would go to a tiebreak.

In the tiebreak, Vinci would be the first one to crack, giving Pennetta the first mini-break at two-points-all. At the first changeover of the seven-point shootout, Flavia was leading 4-2 but some brilliant backhand slices from Roberta gave the unseeded Italian the mini break right back. Now serving trailing 3-4, Vinci's magical backhand slices didn't work this time as she handed Pennetta the mini-break, once again. From there, the server won the rest of the points in that first set tiebreak and in the end, Pennetta would go on to win the opening set, 7-6(4). Could she be the first Italian to win the U.S. Open?

Pennetta Holds Her Nerve to Win Maiden Grand Slam Singles Title

In the opening stages of the second set, it was evident that Pennetta looked a lot more relaxed than Vinci, and was able to open up her shoulders to swing more freely. In less than ten minutes, Flavia had held, broken and held to go up a set and 3-0 lead. Roberta had stopped being aggressive and was being more reactive, allowing her compatriot to dictate from the back of the court. 3-0 quickly became 4-0 as Pennetta looked like she was racing away with the match and the U.S. Open title. Nothing Vinci did seemed to be working until in the next game, some great play from herself and a few errors from Pennetta resulted in Roberta getting one of the two breaks back. Now trailing 1-4, it was Vinci who was looking more comfortable and Pennetta was inevitably, getting nervous. With a hold to 30, Vinci was just one break away from getting right back into this second set. However, the world number 26 began to control her nerves and got a crucial hold of serve to go up 5-2, and one game away from the championship. That hold proved to take something out of Vinci mentally and Pennetta was growing in confidence. Moments later, Flavia would find herself with three championship points. Pennetta only needed the one as she hit an inside-out forehand winner, sealing the match in emphatic style!

The 33-year-old couldn't believe it. She threw her racquet in the air and put her hands on her head, in a state of shock, disbelief and happiness. At the net, Flavia and Roberta would share a warm embrace, as they both knew what a day it had been for Italian tennis and Italian sports in general. Both women were beaming, and no one would have known who won the match judging by how happy both players looked. Pennetta and Vinci, won the 1999 French Open Girls' Doubles title together, and have known each other since they were nine years old. But today, the spotlight was all on Flavia Pennetta. Seconds later, Pennetta would run to her box to hug her coach Salvador Navarro, her fitness coach and her fiancé Fabio Fognini. (Fognini left New York City after his second round loss a week ago but he flew back to watch his fiancée play - and eventually win - the biggest match of her career.)

At the trophy ceremony, both women shared many laughs where Vinci joked around by stealing Pennetta's $3.3 million dollar cheque. However, the most surprising and saddest moment of the ceremony came when Pennetta announced her retirement. "One month ago, I decided that this is the way I would say goodbye to tennis," said the newly crowned U.S. Open champion. "Sometimes it's getting hard for me to compete, you have to fight every week and if you don't in the way I did today, it's going to be bad. It was a really hard decision but I'm really happy I did it. I'm really happy and proud of myself." Pennetta later cleared up any confusion surrounding her retirement, telling Mats Wilander and Barbara Schett of Eurosport: "I will play until the end of this year but it was my last match here in New York."

Regardless of what will happen in the last few months of Flavia Pennetta's career, she will always be a Grand Slam champion, even if she decides to retire tomorrow or if she never wins a professional tennis match again.